七种常用渔药及组合对罗非鱼致病性海豚链球菌的体外抗菌试验

探讨了7种常用抗菌渔药对罗非鱼致病性海豚链球菌的体内外抗菌作用。采用二倍稀释法测定了7种渔药对致病菌的最低抑菌浓度（MIC）和最低杀菌浓度（MBC）;在初筛基础上以MIC为单位,1×MIC、5×MIC、10×MIC和20×MIC下平板抑菌圈直径为参数,分别比较所筛选5种药物抗菌效果并优化最佳参数;利用优化的最佳参数比较5种药物单独用药与联合用药对海豚链球菌的抑菌效果;并通过拌饵投喂给药方式对罗非鱼进行5种药物治疗性给药试验。结果表明,抗菌先锋对海豚链球菌的MIC和MBC最小,分别为6.4、12.8μg/mL,其次是伯乐立康,均为12.8μg/mL;而鱼康和肠炎烂鳃灵即使在1638.4μg/mL下也无抗菌效果。5倍MIC下抑菌圈直径为本试验筛选抗菌药物的最佳参数。5 MIC时,海豚链球菌对伯乐立康和抗菌先锋敏感,对菌必清、菌毒康和海鱼安中度敏感。菌毒康与海鱼安的联合抗菌效果最佳。鱼体内抗菌试验结果表明,抗菌先锋和伯乐立康的治疗有效率超过75%,达到了理想的治疗效果,是防治罗非鱼海豚链球菌病的首选药物。

The antibacterial trial of seven kind common fishery drugs and their combinations to pathogenic Streptococcus iniae from tilapia

Effect of seven common fish drugs on pathogenic Streptococcus iniae of tilapia in vivo and vitro was investigated in this study.The minimum inhibitory concentrations（MIC） and the minimum bactericidal concentrations（MBC） of seven fish drugs were tested by the method of doubling dilution.According to the preliminary screening,comparing the inhibiting and bactericidal effects of 5 fish drugs on Streptococcus iniae respectively,the best parameter was obtained.Then,the best parameter was used to test the inhibiting effect of 5 fish drugs alone and jointly.The anti-bacterial test in vivo for tilapia was performed by remedial administration of mixed feeding bait.The results showed that the MIC and MBC of ETSP were minimum（6.4 μg/mL and 12.8 μg/mL,respectively）,and the GCHBH were both 12.8 μg/mL,but CSP and NSP did not have the inhibitory effects even at the concentration of 1638.4 μg/mL.Among all the parameters,ETSP and GCHBH were the most sensitive to Streptococcus iniae,and EP,FP and DHP were the next.The combination of FP and DHP had the best antibacterial effect among all the trials.This finding also showed that the curative ratio effectively of ETSP and GCHBH exceeded 75%.In conclusion,the two fish drugs had the good performance in prevention and treatment against pathogenic Streptococcus iniae in tilapia.